• Journal of Biomedical Engineering Research
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• v.15 no.4
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• pp.489-497
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• 1994

The most serious problems related to the cardiovascular prothesis are thrombosis and hemolysis. It is known that the flow pattern of cardiovascular prostheses is highly correlated with thrombosis and hemolysis. Laser Doppler Anemometry (LDA) is a usual method to get flow pattern, which is difficult to operate and has narrow measure region. Particle Image Velocimetry (PIV) can solve these problems. Because the flow speed of valve is too high to catch particles by CCD camera, high-speed camera (Hyspeed : Holland-Photonics) was used. The estimated maximum flow speed was 5m/sec and maximum trackable length is 0.5 cm, so the shutter speed was determined as 1000 frames per sec. Several image processing techniques (blurring, segmentation, morphology, etc) were used for the preprocessing. Particle tracking algorithm and 2-D interpolation technique which were necessary in making gridrized velocity pronto, were applied to this PIV program. By using Single-Pulse Multi-Frame particle tracking algorithm, some problems of PIV can be solved. To eliminate particles which penetrate the sheeted plane and to determine the direction of particle paths are these solving methods. 1-D relaxation fomula is modified to interpolate 2-D field. Parachute artificial heart valve which was developed by Seoul National University and Bjork-Shiely valve was testified. For each valve, different flow pattern, velocity profile, wall shear stress and mean velocity were obtained.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 1998.11a
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• pp.172-177
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• 1998

For making high-functional illumination environment and pleasantness to human beings, it is needed to analyze optical characteristics from lightsource as well as to analyze and examine emotional characteristics which respond to optical characteristics systematically. Also, it is Possible to classify lightsource according to function and use based on optical and emotional characteristics systematically and these results can be applied to practical data for professional illumination design field. The aim of this study is to develop technique for evaluating sensibility as well as to accumulate sensibility database through measuring and evaluating emotional reaction to optical characteristics from lightsource. Final aim of this study is to develop simulation and evaluation technique for interior illumination environment, the outline of this paper : 1) operating simulator for various illumination environment 2) developing evaluation methodology for evaluating illumination environment 3) preparing sensibility index through evaluation and analysis The process of this study is as follows. 1) Developing optical evaluation item of lightsource 2) Developing emotional evaluation item of lightsource 3). Analyzing, correlation between optical evaluation item and emotional eveluation item 4) Classifying and selecting object for evaluation 5) Optical measuring and evaluating for lightsource 6) Operating Simulator for illumination environment 7) Emontional measuring and evaluating lightsource and color 8) Developing estimative formula and sensibility index of emotional reaction The results of this study are as follows. 1. Simulator is operated for various illumination environment, and it is proved to be applicable to actual environment. 2. Evaluation and Analysis Techniques is developed for emotional measurement about illumination environment. 3. Estimative formula and sensibility index are prepared, which can estimate the characteristic of lightsource and emotional reaction to interior color

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.7
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• pp.2892-2913
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• 2016

Network virtualization promises to play a dominant role in shaping the future Internet by overcoming the Internet ossification problem. However, due to the injecting of additional virtualization layers into the network architecture, several new security risks are introduced by the network virtualization. Although traditional protection mechanisms can help in virtualized environment, they are not guaranteed to be successful and may incur high security overheads. By performing the virtual network (VN) embedding in a security-aware way, the risks exposed to both the virtual and substrate networks can be minimized, and the additional techniques adopted to enhance the security of the networks can be reduced. Unfortunately, existing embedding algorithms largely ignore the widespread security risks, making their applicability in a realistic environment rather doubtful. In this paper, we attempt to address the security risks by integrating the security factors into the VN embedding. We first abstract the security requirements and the protection mechanisms as numerical concept of security demands and security levels, and the corresponding security constraints are introduced into the VN embedding. Based on the abstraction, we develop three security-risky modes to model various levels of risky conditions in the virtualized environment, aiming at enabling a more flexible VN embedding. Then, we present a mixed integer linear programming formulation for the VN embedding problem in different security-risky modes. Moreover, we design three heuristic embedding algorithms to solve this problem, which are all based on the same proposed node-ranking approach to quantify the embedding potential of each substrate node and adopt the k-shortest path algorithm to map virtual links. Simulation results demonstrate the effectiveness and efficiency of our algorithms.

• Journal of Korean Society on Water Environment
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• v.30 no.5
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• pp.524-531
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• 2014

Korea has been trying to manage water quality of rivers and lakes in many ways. Ministry of Environment is making continuous efforts of operation control improvement such as strengthening effluent standards in sewage treatment plants and expanding Tele-Monitoring System (TMS). However, evaluation method for operations of sewage treatment plants and establishment system of effluent standards are inadequate. The objective of this study is to evaluate for operations of sewage treatment plants using statistics technique such as frequency analysis, percentile, normal distribution analysis. We used the effluent data (BOD, COD, SS) collected at 299 plants in 2012. The values were very low by comparison with standards. The Data followed a normal distribution. We think that distribution characteristics are closely related with effluent standards, especially T-P and BOD. Statistics technique attempted in this study can be used to evaluate for operations of sewage treatment plants and assess the appropriateness of effluent standards based on TBEL(Technology-based effluent limitation). And, this technique can be used to figure out the overall level of plants, the status of each plant and the favorable treatment process for each item (BOD, COD etc.). Data acquired through this method can be used to improve facilities and operation techniques and decide on a sewerage policy.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.335-335
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• 2011

Instability of a thin film attached to a compliant substrate often leads to emergence of exquisite wrinkle patterns with length scales that depend on the system geometry and applied stresses. However, the patterns that are created using the current techniques in polymer surface engineering, generally have low aspect ratio of undulation amplitude to wavelength, thus, limiting their application. Here, we present a novel and effective method that enables us to create wrinkles with a desired wavelength and high aspect ratio of amplitude over wavelength as large as to 2.5:1. First, we create buckle patterns with high aspect ratio of amplitude to wavelength by deposition of an amorphous carbon film on a surface of a soft polymer poly(dimethylsiloxane) (PDMS). Amorphous carbon films are used as a protective layer in structural systems and biomedical components, due to their low friction coefficient, strong wear resistance against, and high elastic modulus and hardness. The deposited carbon layer is generally under high residual compressive stresses (~1 GPa), making it susceptible to buckle delamination on a hard substrate (e.g. silicon or glass) and to wrinkle on a flexible or soft substrate. Then, we employ glancing angle deposition (GLAD) for deposition of a high aspect ratio patterns with amorphous carbon coating on a PDMS surface. Using this method, pattern amplitudes of several nm to submicron size can be achieved by varying the carbon deposition time, allowing us to harness patterned polymers substrates for variety of application. Specifically, we demonstrate a potential application of the high aspect wrinkles for changing the surface structures with low surface energy materials of amorphous carbon coatings, increasing the water wettability.

• Journal of Conservation Science
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• v.32 no.1
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• pp.51-61
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• 2016

'Eojin', king's portraits, had been produced during the Joseon dynasty. The portrait of King Taejo, the founder of the Joseon dynasty, remain at National Palace Museum of Korea and Gyeonggijeon portrait hall in Jeonju and Junwonjeon portrait hall in North Korea that has been recorded in original glass plate photo in 1911. Many replica of Eojin have been made since it is important to preserve and protect original one. In this study, the portrait of King Taejo, which is possessed by National Palace Museum of Korea, was researched for making replication standard version of the original form. It was focused on derivations of each artefacts and drawing lines those had been described on the picture including comparison among three portraits of King Taejo. Producing the replication standard version of King Taejo's portrait, the digital restoration techniques by the method of partition area scanning was applied. Accurate and precise detail result that is taken by digital imaging technique gives additional information regarding the relations among three portraits of King Taejo.

• Journal of Environmental Impact Assessment
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• v.11 no.4
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• pp.247-258
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• 2002

This study aimed at verifying the grain-sized distribution of surface deposits in a tidal flat using multi-spectral Landsat TM. In this study, we employed the grain-sized analysis, PCA and unsupervised classification techniques for analyzing the distribution of deposits. As a result in this study, the unsupervised classification method using PCA image was found to be most useful in classifying tidal flat deposits using satellite data. This method is considerably effective in analyzing not only the aspects of distribution in terms of accumulated deposits and erosion, but also the changes in seaside topography and shoreline. The grain-sized distribution analysis indicates that the mud flat inside the Cheonsu-bay tidal flat is distributed, the mixed flat located in the middle, and the sand flat distributed near the sea. The sand flat is dominant around the southern part of Seomot isle and its beach. On the other hand, the mud and mixed flat is dominant on the western part. Likewise, the western coast of Seomot isle and its beach is significantly affected by waves facing the offshore. However, the eastern side of the bay could be a site for the evolution of tidal flat made of fine materials where it is less affected by ocean waves. These results show that multi-spectral satellite data are effective for the classification of distribution materials and environmental impact assessment and continuous monitoring. In particular, the research on environmental deposits can provide important decision-supporting information for decision-making on seaside development, by analyzing the progress of deposits and environmental changes.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.11 no.5
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• pp.92-103
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• 2008

Development of new approaches to achieve naturally good ecological potential of forest road cut-slope by making the best use of advantages of gabion systems with vegetation base materials to prevent slope failure and erosion, in the area with highly erodible soil. As a result on the type analysis of gabion systems already installed in road cut-slopes, gabion systems were generally established to prevent slope failure. Existing gabion systems can be divided into monolithic and modular system and can be divided into ten subtypes according to the purpose of establishment and combination of other measures. As a result on the monitoring of erosion amount from forest road cut-slopes in the test applications, the order of erosion amount from largest to smallest is as follows : the curved road cut-slope site where normal gabion system was established ($7,911cm^3$); the control site ($7,632cm^3$); the straight road cut-slope site where normal gabion system was established ($7,301cm^3$); the curved road cut-slope site where the new gabion system was established ($5,684cm^3$); and the straight road cut-slope site where the new gabion system ($5,325cm^3$). Therefore, the result shows that the new gabion system is more effective than the normal gabion system to reduce erosion amount from forest ! road cut-slopes. During the study period, vegetation coverages of the straight and curved road cut-slope site where the new gabion system was established were about 45% and about 36%, so average vegetation coverage of the sites where the new gabion systems was established was higher than the sites where the normal gabion systems was established. Therefore, it was concluded that the new gabion system can be more effective for cut-slope revegetation.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2004.11a
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• pp.557-563
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• 2004

Korean cadastral system keeps graphical maps made by the plane table method from 1910's. The fact is that the graphical maps grafted on paper cover about 95% of the whole land (MOGAHA, 1999). The needs are arising to transform the graphical cadastre to a digital one in compliance with modem technologies. Korean government has already digitise the old maps until last year. A nation-wide land information system, Parcel-based Land Information System, was established upon the digitised map database. However, the accuracy of the digitised coordinates hardly meet the citizens' needs because it cannot exceed that of the paper maps. The definite solution will be surveying all the parcels again and making new digital maps. However, commencing a project for resurveying 34 million parcels will require enormous amount of time and manpower. The strategy should be dividing the country into county-wise or grid-wise pieces and surveying one piece by one piece. Municipal governments of counties, cities or urban districts will be the propelling bodies of the project but the costs will hardly be affordable at a time. For the purpose of resolving the financial problem, each municipality can split its own project into smaller pieces by year base. There is accordingly a great possibility to create inconsistency over the divided project areas caused by different techniques applied, different equipments used and/or mismatches between the project borders. It provides some merits at the same time. The people in project completion areas will be satisfied with the enhanced accuracy and feel safe in land transaction and, in turn, soundly improves overall nation-wide economic situation. Therefore, the main issue of the thesis shows how to make the cadastral re-survey project scalable. Guidelines for how to perform the projects will be derived from a experienced case.

• Journal of KIISE
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• v.43 no.2
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• pp.163-176
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• 2016

The contention overhead on the same channel in an NoC architecture can significantly increase a communication delay due to the simultaneous communication requests that occur. To reduce the overall overhead, we propose task-to-tile binding techniques for an NoC-based manycore platform, whereby it is assumed that the task mapping decision has already made. Since the NoC architecture may have multiple memory tiles as its size grows, memory clustering is used to balance the load of memory by making applications access different memory tiles. We assume that the information on the communication overhead of each application is known since it is specified in a dataflow task graph. Using this information, this paper proposes two heurisitics that perform binding of multiple tasks at once based on a proper memory clustering method. Experiments with an NoC simulator prove that the proposed heurisitic shows performance gains that are 25% greater than that of the previous binding heuristic.